/Engine/Source/Runtime/ApplicationCore/Public/GenericPlatform/GenericPlatformInputDeviceMapper.h
Functions to provide compatibility between the old "int32 ControllerId" and the newFPlatformUserIdandFInputDeviceIdstructs. Remap aFPlatformUserIdto a ControllerId that is needed by legacy code. Use this function to add compatibility to platforms that may not have implemented this device mapper yet.
True if this maps to a real user
bool RemapUserAndDeviceToControllerId ( [FPlatformUserId](API\Runtime\Core\Misc\FPlatformUserId) UserId, int32 & OutControllerId, [FInputDeviceId](API\Runtime\Core\Misc\FInputDeviceId) OptionalDeviceId )